Circus cyaneus (dark blue)
Two recognized; C.c.hudsonius (William H. Hudson, naturalist 1842-1922) is NA subspecies.
NA subspecies from Alaska and northwestern Canada south throughout southeast Canada and US to northwest Mexico and southeast Virginia; winters south to northern South America.
A diverse variety of open country, such as grassland, meadows, moorland, scrub, cultivated fields with grass-like crops, wetlands, young conifer farms, and tundra. Will winter near ploughed land. Prefers flat or gently sloping land, but can also be found on mountainsides at least up to 2500 meters. Perches on ground, rocks, trees, and sometimes poles. Sleeps on ground, often in communal roosts with 10-100 individuals.
Most of a Harrier’s diet consists of small vertebrates found in the open countryand wetlands; they will eat voles, mice, rats, ground squirrels, and young rabbits and hares. They also take some birds and invertebrates, such as grasshoppers, crickets, reptiles and amphibians, as well as bird’s eggs. In winter, the Harriers will eat carrion. They hunt in a slow, low, foraging tilting, buoyant flight, balanced by their long tail and upswept wings. With their facial disks, they rely on hearing their prey, and take their victims on the ground. Harriers are solitary hunters, traveling long distances (up to 10 km. or more) from their roosts or nests.
Mid April to May in NA. Males are polygynous, often mating with 2-3
females (up to 7 has been reported). The nest, built completely by the female, is a pile of small sticks and grass on the ground in dense grass, scrub, marshy growth, or cropland. This last location is risky, as the well-hidden nests are often run over by farm machinery. Clutch is 3-7+ eggs, depending upon available food supply, laid at intervals of 1-3 days. Breeding first occurs usually at 2-3 years of age; some breeding after the first year.
Migratory, especially in northern part of range, traveling south to Central America, Colombia, and Venezuela. May be resident in southern US, often dispersing in winter to better feeding areas. Fall migration August to early November. Spring migration is March to May.
Not threatened. In NA, stable with slight decline due to habitat loss with more intensified farming and disappearance of wetlands.